The City of Cape Town has a policy restricting what you can do with new boundary walls at your home.
For side and rear boundaries, walls are limited to 2.1m high.
For street facing boundaries, the maximum height is 1.8m.
In addition, the City does not allow full height solid walls along the full length of street facing boundaries. At minimum 40% of the length of the street frontage must be " visually permeable"
This means either not walled or walled with something which is see through, gates or palisade fencing. If your driveway was open to the street or had a steel gate you could see through for instance, then this would count towards the 40% requirement.
It may be possible with a good motivation to appeal for a departure to allow a variation to this policy, but like everything that requires specific permissions, there is no guarantee of approval.